Extraction of Essential Oils

October 20, 2009 | By admin In aromatherapy essential oils |

Only nature can produce whole essential oils. Essential oils are tiny droplets contained in glands, glandular hairs, sacs, or veins of different plant parts, like leaves, bark, flowers, stem, roots and fruits. They are the “essence” of the particular plant that giving the plants its unique scent.

There are three principal methods of extracting essential oils from aromatic plants. These are: distillation process; expression process; extraction using volatile solvents; and enfleurage process.

Distillation Process
Distillation process or steam distillation is the most common process method for obtaining essential oils from a plant. The process involve heating and the steam is force into a vat of plant material, where it breaks open and reptures these glands releasing the precious oils, vapor is formed, then cooling the vapor until it becomes liquid. This is when the essential oils are collected.

Distillation is an economical and popular method used in essential oils extraction. However , it still may take hundreds, or even thousands pound of plant parts to distill a single pound of the essential oils. That’s why, some essential oils will vary greatly in their cost.

Expression Process
Expression process also know as cold-press process, this method is only used for citrus fruit. The essential oils in citrus fruits are situated close to the surface of the peel and are easily obtained by squeezing and scarification (finely puncturing the peel). Expression methods include the sponge method and machine abrasion, the former being more traditional and producing a very pure essential oil.

You can experiment at home with hand expression and produce small quantities of your own citrus essential oils. Wash and dry the fruit and cut off segments of peel. Using your fingers, squeeze the peel over a small bowl to collect the drops of essential oil. If you squeeze a lemon or orange rind into a candle flame, you can see tiny fireworks. This is because essential oils are flammable, you can see firsthand that they are present.

Solvent extraction

Another method employed is called solvent extraction. Technically, this process does not produce an essential oil. Rather the outcome is a highly scented concentrate used primarily in the perfume and food industries. Solvent is used to “pull out” the soluble plant molecules; therefore they are not complete. For those plant containing only a small amount of essential oil, solvent extraction processes are used. The main advantage is that this method is gentle, but the resulting essential oils include non-volatile waxes and plant dyes, as well as the essential oil itself. Nonetheless, these essential oils are considered by many authorities to be fine for use in aromatherapy. The main solvents used in modern production are volatile hydrocarbons (such as hexane).

Enfleurage Process

An intensive and traditional way of extracting oil from flowers. The process involves layering fat over the flower petals. Over time and many layering, the fat has absorbed the essential oils. Once the fat is saturated with fragrance, it is then called the “enfleurage pomade”. The enfleurage pomade then soaked in alcohol to draw the fragrant molecules into the alcohol. The alcohol is used to separate and extract the oils from the fat. The alcohol is then allowed to evaporate, leaving behind the absolute pure essential oils. The spent fat is usually used to make soaps since it is still relatively fragrant.

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